1. Field of the Invention
The present invention relates to an axis or a roller body on the basis of at least one first thermoplastic material which is processable in an injection molding process.
This invention refers also to a method of producing this axis or this roller body, and the use of this axis or roller body, as well.
2. Description of the Related Art
Conventional rollers include an axis produced of metal or alloys.
This axis is bonded in a separate production step manually or mechanically to one or several rubber roller(s) or to one or several roller(s) of a thermoplastic material.
This bond may be an adhesive bonding, a pressing on, an engaging, etc.
These rubber rollers can, however, be directly vulcanised onto this axis.
Before such rollers can be used in modern electronic appliances such as printers, labelling machines, photo copy apparatuses, fax machines, etc., an extensive surface treatment such as grinding, roughening, etc. of the roller(s) is necessary.
Due to the various materials, the processing and post processing of such rollers is correspondingly expensive.
In order to achieve the desired geometry at the metal axis, such as for instance the diameter of the shaft, grooves, driving elements, etc., extensive post-treatments are necessary.
The natural large weight and also the possible electrostatic charging of the metal axis can have negative influences.
In order to minimize the drawbacks and the restrictions in selecting the geometry at the metal axis, axes have been developed on the basis of plastic materials.
Such conventional plastic material axes incorporate, however, still the drawback of the separate assembling of the roller of rubber or of a thermoplastic material, coupled with the above mentioned extensive surface treatment.
In the JP-A-03-24926 a method of producing guide rollers for the use in video cassette apparatuses (video tape recorder, VTR) and in cassette tapes for VTR is described.
Until the date of this Japanese invention such guide rollers were produced of only one single material.
This had the following drawbacks:
At the outer portions of such guide rollers recessed areas occur which necessitate a post-treatment by a machine.
Furthermore, when selecting materials always a compromise between glideability and wear resistance had to be reached.
According to JP-A-03-24926 these drawbacks are eliminated by the use of 2 different materials.